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Forum Index : Windmills : Fisher & Paykel Micro Hydro
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Don B Senior Member  Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi John, If your clamp-on ammeter is intended for both AC and DC use, then it will be a Hall effect device, and will need to be zeroed before use as Tony describes. As he indicates, it will need to be re-zeroed before each use, as the zero always seems to shift slightly. Without knowing your particular instrument, it is possible that you may need to select whether you are measuring AC or DC current, but this should be clear from inspecting the selector switch markings. One final point that applies to all clamp on instruments is that it is important to keep the jaws of the clamp clean. The face of the jaws will have been ground so that, when shut, they have a minimal air gap, and you need to keep them that way. Rust, in particular, can be a problem, so never leave any moisture on the jaw faces. Regards Don B |
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| Hydro John Newbie  Joined: 31/10/2011 Location: United StatesPosts: 35 |
Thanks both Tony and Don, The meter does read both AC and DC, and has a select button and the Rel delta button does zero out the reading, therefore from what you have told me I have a Hall effect device. Now I can begin recording information with some assurance that the readings are reasonably accurate. I was able to repair my penstock today and hope to get back to testing soon. Will keep you posted. By the way, Tony, are you still interested in the turbo project? Thanks again John Hydro John |
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| Warpspeed Guru  Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I have a few old deceased turbos here that I have been on the verge of tossing out with the rubbish for quite a long time. Roughly what is the nozzle flow area you are able to run with your current Pelton wheel? I will try to find a turbine wheel and housing that might end up with a roughly comparable water flow to what you now have. Anything vastly larger or smaller probably would not be all that helpful for direct comparison. These turbocharger turbines and housings have a very complex curved shapes, and very small leakage clearances. They have been developed to be extremely efficient with gas flow, and should work even better with water. If you compare one of these, to pictures of a big Francis hydro turbine, they look absolutely identical in shape and construction. I have very high hopes for this !!! Anything I can find around here, you can have for free. Let's see how it goes first. If it looks optimistic, we can then start thinking a bit more about some more suitable bearings, seals, and a shaft coupling. Cheers, Tony. |
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| Hydro John Newbie Joined: 31/10/2011 Location: United StatesPosts: 35 |
[quote=Warpspeed]Roughly what is the nozzle flow area you are able to run with your current Pelton wheel?[/quote]Most of my tests have been in the 50 GPM to 55 GPM which give about 140 watts after rectification. I have done a few tests using larger nozzles to increase the flow to about 100 GPM. The power goes up but the effeciency factor goes down. I tried using wider cups on the pelton wheel but with little success, but I want to do more tweaking and testing in this area. I think it would be wise to wait until I get my dam built before testing the turbo. Hydro John |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
The smallest turbine housing I have here has very roughly about a 25mm diameter inlet flow area. Difficult to estimate, because it is a cone wrapped around the turbine, and it isn't round in cross section anywhere. That 25mm diameter inlet flow corresponds to "A2" in the following sketch. 
In an earlier post you mentioned a 15mm nozzle, this is going to flow a whole lot more water, maybe about 2.8 times as much volume. Anyhow, if your 15mm nozzle flows 4.0 Litres/sec with the static head pressure that it has, that approximates a flow velocity of around 2.25 metres/sec hitting your Pelton wheel. The same velocity curling around the much smaller 52mm diameter turbo turbine comes out to very roughly 828 rpm. A very usable speed, if all these assumptions are correct. And 2.8 times the flow should hopefully develop 2.8 times the power. Cheers, Tony. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
ZERO DC AMPS Hi Herb, pressing the REL button for DC amps will soon be second nature to you. I use my clamp meter on every job. My meter usually has an error of 1.8 amps on the DC 400 range and 0.78 Amp on the DC 40 range that needs to be zeroed out. Once in a blue moon it will drift towards zero while I am using it so it pays to check and recalibrate every few minutes. My meter also looses its zero calibration if it goes into sleep mode. It pays to measure the voltage at the same time as taking amp readings if you can. If the amps are dropping it will tell you a lot if the voltage is rising, stable or dropping at the same time. If you can't get at a certain cable with the clamp it is also possible to use the REL button to subtract one amp reading from another and the meter will show the difference. yahoo I'm confused, no wait... maybe I'm not... |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
John, If you can pm me your postal address, I will get it into the mail. Cheers, Tony. |
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| Hydro John Newbie Joined: 31/10/2011 Location: United StatesPosts: 35 |
[quote=Warpspeed]In an earlier post you mentioned a 15mm nozzle, this is going to flow a whole lot more water, maybe about 2.8 times as much volume. Anyhow, if your 15mm nozzle flows 4.0 Litres/sec with the static head pressure that it has, that approximates a flow velocity of around 2.25 metres/sec hitting your Pelton wheel. The same velocity curling around the much smaller 52mm diameter turbo turbine comes out to very roughly 828 rpm. A very usable speed, if all these assumptions are correct. And 2.8 times the flow should hopefully develop 2.8 times the power.[/quote] My flow thru nozzle tests show that with 2-15mm nozzles I get about 52 GPM. That is about 26 GPM thru each nozzle. This set up gives about 140 watts. I have done some tests with a single 21mm which gives about 55 GPM, but no output results yet. I can make almost any size nozzle, so if there is a size you would like me to do some tests with, let me know. I sent you a PM with my PO address back in Dec., but obviously I didn't do something right since you didn't get it. I'll try again. Let me know if you don't get it. Thanks [quote=Yahoo2]pressing the REL button for DC amps will soon be second nature to you. I use my clamp meter on every job. My meter usually has an error of 1.8 amps on the DC 400 range and 0.78 Amp on the DC 40 range that needs to be zeroed out. Once in a blue moon it will drift towards zero while I am using it so it pays to check and recalibrate every few minutes. My meter also looses its zero calibration if it goes into sleep mode. It pays to measure the voltage at the same time as taking amp readings if you can. If the amps are dropping it will tell you a lot if the voltage is rising, stable or dropping at the same time. If you can't get at a certain cable with the clamp it is also possible to use the REL button to subtract one amp reading from another and the meter will show the difference.[/quote]Thanks for the tip. John Hydro John |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
John, I did receive the address you sent me originally. I just forgot that you had, and it's still there. The turbo is now packed and addressed, and will be in the mail today. We can discuss a few further ideas once it has arrived. This is something I have been hoping to try out for a very long time, and am now getting quite excited anticipating the results. Cheers, Tony. |
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| nicholasgeo Newbie Joined: 27/03/2013 Location: CanadaPosts: 3 |
Hello John I have a vert similar set-up to you. I wired it as a star type rewire and have the same problems getting it up to speed...I get 12.3volts and produce about 1 amp. We you able to resolve your wiring issue? Is so, would you mind sharing the configuration you did on the rewiring. Thanks, Nick |
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| jthwaites Newbie Joined: 29/06/2013 Location: AustraliaPosts: 1 |
I have been mucking about with these motors for 15 years now but not as seriously as most it seems. I thought it might be a good idea to use a battery charger with a switch mode power supply fron end. This would take the 3 ph rectified voltage from the FP motor and provide a well regulated battery charging output. Comments on this would be appreciated - is it a dumb idea, can you get a battery charger with switch mode front end? Most electronic gear like TVs etc run on 100 V DC (as will brushed AC motors, drills, food processors etc but not the fridge or washing machine) and will run on the rectified output of the FP motor - http://www.sustainability.fm.uwa.edu.au/welcome/exercise_bik e_generator Use this to charge a battery bank (typically 48V for a UPS). see http://www.sustainability.fm.uwa.edu.au/welcome/ups_low_cost _independent_power_supply Use the UPS output to run the house. The rectifieris shown on the bottom of this page http://www.sustainability.fm.uwa.edu.au/welcome/wind_turbine __home_made |
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| gww1 Regular Member  Joined: 14/06/2013 Location: United StatesPosts: 63 |
Schnider does have a high voltage charge controller that will take about 600 volts and charge a 48 volt battery bank but it cost about $1100 so I don't think it would be cost effective. You do have a long wire run at 400'. Cheers gww |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I have done this many times, designed standard readily available modular switching power supplies into many commercial products as high performance battery chargers. The Chinese switchers are particularly good value and work very well. And they will work over an amazingly wide input voltage range, with either ac (of any reasonable frequency) or direct high voltage dc input. It is hardly worth building a battery charger any other way these days. 
Most of these supplies come with nominal set fixed output voltages that are way too low for battery charging, and cannot be simply "tweaked up" high enough in output voltage to be useful for battery charging. These supplies invariably come with a pair remote voltage sensing terminals that can be connected to regulate the voltage at a remote load. http://5af5e3de5795a966dd90-e9792bbf34570cde028937f7b1897875 .r53.cf3.rackcdn.com/uploads/images/514c94ef043844f39ff26ab6 0ab285db The voltage sense terminals are usually connected to the main dc output terminals (inside the supply) either through resistors or sometimes with a resistor with a diode in parallel in each leg, and sometimes with removable bridging links as in the above picture. The trick is to fool the supply into maintaining 12.0v, 24.0v or 48.0v (or whatever) on its sense terminals, while actually providing a usefully higher output voltage across the main dc output terminals. For instance, you could build a simple resistive voltage divider with two resistors that supply 12.0 volts across the sense terminals when the dc output voltage of the main supply is up at 14.1 volts. But you can do much more than that! Switch between boost charge voltage, and float voltage, or add temperature compensation to the float voltage with some appropriate circuitry. If you want something really fancy, how about a Unitrode UC2906 intelligent lead acid battery charger control chip to control the sense terminals? This is all fairly straightforward. If the sense terminals are fed through resistors within the switching power supply, you need to take that into account when designing a voltage divider. If diodes are also fitted internally, these will almost certainly need to be removed. This is a really great way to build a very efficient battery charger that can have as few or as many advanced features as you wish. Cheers, Tony. |
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